Structure and thermochromism of spiropyrans. Triplet mechanism of the thermal cleavage/closure of the pyran ring

Kalnin'sh, K. K.

doi:10.1007/bf02903537

Cited by 5 publications

(8 citation statements)

References 6 publications

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“…The comparison of spiropyran and merocyanine structures shows that the bond between b(26)-b(27) atoms in the first molecule has a cis-configuration and in the second transconfiguration. So, looking for the best way to convert one molecule to another, it is necessary to foresee the trans-cisisomerization relative to C(26)-b (27) bond and then change the hybridization from sp 3 to sp 2 of nuclear orbitals of the spiroatom C (25). Besides, there is a need to find the optimal configuration of phenyl part of the molecule by the investigation of rotation of this fragment round the axis C(27)-C (28).…”

Section: Resultsmentioning

confidence: 99%

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Conformational States of the Spiropyran Molecule

Kovalenko

Kondratenko

Lopatkin

2015

International Journal of Photoenergy

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The form of the potential surface of the ground state was investigated on the basis of indoline spiropyran. As a result of this work the rotamers of an open-ring form of the spiropyran molecule were discovered, and the existence of the most probable rotamers was justified. The 3D potential surface of the ground state of the spiropyran molecule was built. The route of the isomerization of the molecule was discovered and values of barriers for this reaction were found. The part of the isomerization route that is responsible for changing the hybridization of spiroatom from sp3to sp2was found.

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Section: Resultsmentioning

confidence: 99%

“…Plenty of scientific works are devoted to the investigation of the spiropyran molecule [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. It is necessary to say that at such interest in spiropyrans during the half a century there is still no clear opinion about the mechanism of spiropyranmerocyanine switching.…”

Section: Introductionmentioning

confidence: 99%

Conformational States of the Spiropyran Molecule

Kovalenko

Kondratenko

Lopatkin

2015

International Journal of Photoenergy

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“…10−12 The thermochromic color change of a compound/material is distinguished often by eye, occurring over a small or sharp temperature interval. For inorganic compounds, this transition is frequently due to a change in the crystalline phase, to a change in ligand geometry, as a result of charge transfer, 13 modifications in the chemical structure, 14 or to a change in the number of molecules of the solvent in the first coordination sphere. 15,16 A fewer known examples are as a result of equilibria between complexes in solution or to equilibria between different molecular structures in the case of organometallic compounds.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Thermochromism, defined as reversible change in the color of a compound when it is heated or cooled, has received little attention as an energy harvesting mechanism. − The thermochromic color change of a compound/material is distinguished often by eye, occurring over a small or sharp temperature interval. For inorganic compounds, this transition is frequently due to a change in the crystalline phase, to a change in ligand geometry, as a result of charge transfer, modifications in the chemical structure, or to a change in the number of molecules of the solvent in the first coordination sphere. , A fewer known examples are as a result of equilibria between complexes in solution or to equilibria between different molecular structures in the case of organometallic compounds . The thermochromic transition temperature of a pure substance may be greatly changed by dispersing the compound in a solid matrix or by mixing it with other substances.…”

Section: Introductionmentioning

confidence: 99%

Ionic Liquids–Cobalt(II) Thermochromic Complexes: How the Structure Tunability Affects “Self-Contained” Systems

Billeci

Gunaratne

Licence

et al. 2021

ACS Sustainable Chem. Eng.

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With the aim of obtaining thermochromic systems with potential applications in solar energy storage, we evaluated the behavior of some sugar-based ionic liquids (ILs)−Co(NTf 2 ) 2 complexes, in IL solution, as a function of temperature. Different structural changes on the cation, the nature of the anion, and the nature of the IL used as the solvent were considered. The analysis of the above factors was carried out through a combined approach of different techniques, that is, variable temperature UV−vis and NMR spectroscopies, conductivity, and thermal gravimetric analysis. The thermochromic systems were analyzed both as solutions and as thin films, and the data collected highlight the defining role played by both the cation structure and the solvent nature in determining their performance. Most of the investigated systems show a chromogenic transition from pink to blue, occurring in a temperature range suitable for practical applications (40−60 °C). Interestingly, when embedded in a polymeric matrix, thin films with high recyclability and long life are also described.

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“…2E), the activation energy of the thermal relaxation was calculated as 34 kJ mol À1 , which is comparable with other organic photochromic and thermochromic systems such as spiropyrans (9 to 27 kJ mol À1 ). 21 This relatively low energy barrier explains the short half time of thermal relaxation for shyRFP (4 s), relative to almost all other photochromic FPs including Dronpa (840 min), 9 mTFP0.7 (4 min), 10 rsTagRFP (65 min) 12 and rsCherry (40 s). 11 To investigate the inuence of the protein chromophore protonation state on the photo-and thermochromism, kinetic measurements of photoactivation ( Fig.…”

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confidence: 98%

A photochromic and thermochromic fluorescent protein

2014

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We report a photochromic and thermochromic fluorescent protein that exhibits a reversible and striking visible colour switch between yellow and red. The protein has been characterized in terms of its light, temperature and pH-dependence. Based on a mutational analysis we propose that the colour switch mechanism involves chromophore protonation coupled with E-Z isomerization.Photochromism is a change of colour induced by irradiation with light, while thermochromism is a change of colour due to a change of temperature. 1 Both photochromism and thermochromism have been observed in inorganic and organic compounds, however thermochromism is much less common in biological systems. 1b,2 One mechanism by which molecular photochromism can occur is a photo-induced isomerization to a second stable state with a different absorption wavelength. For such molecules, the rate of conversion is accelerated with increased temperature, and therefore the photochromic and thermochromic properties are intimately coupled. 1b,3,4Only a handful of classes of naturally occurring photochromic proteins have been identied. Representative classes of photochromic proteins include bacteriophytochromes, 5 rhodopsins, 6 and uorescent proteins (FPs). 7 The rst photochromic FP to be described was the reversible 'kindling' protein, asFP595, from the sea anemone Anemonia sulcata. 7 Reports of a number of other reversibly photochromic FPs followed, including many with faster switching properties or red-shied emission colour, including: Dronpa, 8 rsFastlime, 9 mTFP0.7, 10 rsCherry, 11 and rsTagRFP. 12 Mechanistic investigations of photochromic proteins have revealed that the photoswitching mechanism is typically based on coupled protonation changes and E-Z isomerizations of the protein chromophores. 9,11,13,14

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Structure and thermochromism of spiropyrans. Triplet mechanism of the thermal cleavage/closure of the pyran ring

Cited by 5 publications

References 6 publications

Conformational States of the Spiropyran Molecule

Conformational States of the Spiropyran Molecule

Ionic Liquids–Cobalt(II) Thermochromic Complexes: How the Structure Tunability Affects “Self-Contained” Systems

A photochromic and thermochromic fluorescent protein

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